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Knowledgebase: ALMA Observing Tool (OT)
Should I be concerned about warning messages in the OT after validation of my scheduling blocks?
Posted by Sarah Wood, Last modified by Rein Warmels on 28 February 2018 06:57 AM

Certain types of observing program require special attention by an ALMA Staff Phase 2 Group (P2G) member after the PI has submitted the Scheduling Blocks (SBs), in order to ensure successful execution at the telescope and the highest possible quality data. This can be, for example, adding suitable calibrators for high frequency and long baseline projects, adding extra bandwidth for projects with narrow aggregate bandwidth, adding “off” reference positions for Total Power, or slightly optimizing frequency tunings. Some of these are described in the “Phase 2 Quickstart Guide” document, available from the Documentation page in the ALMA Science Portal.

Many of these types of observing program result in warnings in the ALMA-OT that are intended only to inform the ALMA P2G staff member and do not affect the submission of the SBs by the PI.

All non-standard observing modes will produce such a warning. As described in the Science Portal under 'Documents & Tools'

  • Bands 8, 9 & 10 observations
  • Band 7 observations with maximum baselines > 5 km
  • All polarisation observations
  • Spectral Scans
  • Bandwidth switching projects (less than 1GHz aggregate bandwidths over all spectral windows)
  • Solar observations
  • VLBI observations
  • Non-standard calibrations (user-defined calibrations selected in the OT)

Other observing programs that will produce such warnings include those that have:

  • Time constrained observations
  • Spectral windows that are close to the edge of a receiver band (“Spectral spec. may fail during execution due to the Earth’s motion”)
  • Spectral windows that are centered on or outside of an anti-aliasing filter (“Spec. window has centre set near or outside anti-aliasing filter”)

If warnings of this kind are noticed when validating a project they can safely be ignored and the SBs can be submitted as normal. ALMA staff will review (and, if necessary, modify) these SBs prior to their execution at the telescope.

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